Fault code P0758 – a step-by-step guide to diagnosing and fixing it

Error code P0758 is displayed and the check engine light is on - what does this mean?

The OBD/EOBD system detects a fault in the gearshift solenoid valve B of the transmission, specifically an electrical fault in the circuit. This DTC P0758 concerns the automatic transmission and its electronic control unit, whereby the shift solenoid valve B is not functioning properly.

What are the possible causes of this fault code?

• Defective shift solenoid valve B in the transmission
• Damaged wiring to the shift solenoid valve
• Loose or corroded plug connections
• Defective transmission control unit (TCM)
• Contaminated or used transmission oil
• Internal gearbox damage or blockages
• Short circuit or interruption in the electrical circuit

What symptoms occur in parallel with fault code P0758?

• Shifting problems: The automatic transmission shifts jerkily or with a delay between gears
• Emergency running program: The transmission switches to safety mode and stops in one gear
• Increased fuel consumption: The engine operates inefficiently due to incorrect gear selection
• Loss of engine power: Noticeable reduction in driving performance, especially when accelerating
• Unusual noises: Rattling or buzzing from the transmission area

How can the problem of error code P0758 be rectified?

• Repairing this trouble code requires a systematic diagnosis and targeted measures.
• Complete electrical check of the wiring and plug connections to the shift solenoid valve B with subsequent replacement of damaged components
• Replace the defective solenoid valve B after removing the transmission pan and cleaning the working area
• Change the transmission oil and filter completely, as contaminated oil can block the solenoid valves
• Diagnose the transmission control unit (TCM) and have it repaired or replaced if necessary
• Carry out an internal gearbox inspection if mechanical damage is the cause
• Clear fault code and test drive to check proper function